Our work is directed towards understanding of cellular motility and its relationship to glycolysis, with emphasis on the rate-limiting enzyme phosphofructokinase, and of the regulation of these processes by the second messengers -- cAMP and Ca++. Specific aims in this area are: (1) determination of the roles of actin and actin-binding proteins in the regulation of rabbit muscle phosphofructokinase, (2) establishment of a recognition sequence for calmodulin and identification of the protein-binding site in calmodulin, and (3) understanding of the dual regulation of smooth muscle myosin light chain kinase by calmodulin and the cAMP-dependent protein kinase. Methodology includes fluorescence spectroscopy, chemical modification, gel electro-phoresis, and measurements of catalytic activity. This information may contribute to understanding of Tarui's disease, a deficiency of skeletal muscle phosphofructo-kinase; malignant hyperthermia, which is accompanied by accelerated substrate cycling between phosphofructokinase and fructose diphosphatase; and viral transformation.